The UCC28070A is a switch-mode controller used in interleaved boost converters for power factor correction. The UCC28070A device requires few external components to operate as an active PFC preregulator. It operates at a fixed frequency in continuous conduction mode. The operating switching frequency can be programmed from 10kHz to 300kHz by a single resistor from the RT pin to ground. The magnitude and rate of optional frequency dithering may also be controlled easily.

The internal 6V reference voltage provides for accurate output voltage regulation over the typical world-wide 85V_AC to 265V_AC mains input range from zero to full output load. The reference may also be used to set a peak current limit. Regulation is accomplished in two loops. The inner current loop shapes the average input current to match the sinusoidal input voltage under continuous inductor current conditions. A single multiplier output is shared between the two current amplifiers to ensure close matching of the currents in the two phases. A Zero-Power detector disables both the GDA and GDB outputs under light-load conditions.